Hyperphosphataemia after Fenbendazole in dogs

The FDA has received 33 reports of hyperphosphataemia in dogs after Fenbendazole. That is 0.6% of all reports for this medicine, compared with 0.6% across reports for all dog medicines.

33Reports

88%Marked serious

12%Recovered

33%Died or euthanised

12 daysTypical onset

How soon it started

Same day

4 14%

1–2 days

7 25%

3–7 days

3 11%

1–4 weeks

7 25%

Over a month

7 25%

How the animals did

Recovered

4 12%

Still unwell when reported

14 42%

Died

2 6.1%

Euthanised

9 27%

Not known

4 12%

Problems reported at the same time

22 67%

20 61%

16 48%

15 45%

13 39%

12 36%

12 36%

11 33%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Fenbendazole treats intestinal worms and some other parasites.

Questions owners ask

Can Fenbendazole cause hyperphosphataemia in dogs?: 33 reports link the two, but a report alone does not prove the medicine was the cause: other illnesses, other medicines or coincidence can be involved. Your vet can judge it for your animal.
How soon after a dose was it reported?: In half of the reports with dates, it started within 12 days of the first dose.
What should I do?: Don't give another dose until you've spoken to your vet, and keep the packaging so you can tell them the product and dose. Your vet can also report it to the FDA (or you can, through the manufacturer or FDA form 1932a).

Hyperphosphataemia with similar medicines

Hyperphosphataemia after Pyrantel + Sarolaner (Simparica Trio) 62 reports · 0.1% of its reports
Hyperphosphataemia after Febantel + Praziquantel + Pyrantel (Drontal Plus) 26 reports · 0.4% of its reports
Hyperphosphataemia after Pyrantel 33 reports · 0.7% of its reports

All reported side effects of Fenbendazole in dogs · Medicines most reported with hyperphosphataemia